Ignoring is the only way to deal with people you don't like.
Also, I suspect this control scheme is far too much work.
And, there are a lot of people opposed to such schemes
on principal reasons.

Maybe the analog of a killfile would be a useful feature
for those who long for a better signal/noise ratio
(although
I really feel this is not so bad currently).
Just give every user the option to list other users that
he never wants to see. Then he won't see them in the
CB, and won't see any nodes they created. Problem solved.

Besides that, weeding out inactives might be worth some
effort, if the system needs it for performance/maintenance
reasons. Usually, though, the number of people registered
is important in getting advertisement returns, so this might
not be so clueful after all.